require 'pg'
#--

class BD
  
  @tabla
  def initialize(tabla)
    return "Tabla invalida" if tabla.length=0 || tabla=nil
    
    @con=PGconn.connect("localhost", 5432, '', '', "acceso", "postgres", "")   
    @tabla=tabla
    
  end
    
    
  def
end
conn = 

res  = conn.exec('select * from empleados')

res.each do |row|
  row.each do |column|
#   print column
#   (20-column.length).times{print " "}
  end
  puts
end